Which garden is famous for its collection of plants and landscapes and is associated with the Royal Horticultural Society?

Wisley Garden is renowned for its vast collection of plants and diverse landscapes, making it a prominent site in horticultural practices. It is closely associated with the Royal Horticultural Society (RHS), which promotes gardening through exhibitions, educational programs, and research. Wisley serves as one of the RHS’s primary locations where visitors can experience expertly curated gardens, various plant collections, and innovative horticultural displays.

This association enhances its significance as a leading center for gardening and plant research in the UK. The garden attracts numerous horticultural enthusiasts and serves as a resource for inspiration, education, and recreational enjoyment.

While other options like Botanical Gardens and Royal Botanic Gardens generally refer to various public gardens that may have impressive collections, they do not specifically denote the direct link to the RHS that Wisley Garden possesses. St James's Park, while also notable, is primarily a traditional park with landscaped gardens and does not focus on the horticultural aspects associated with the RHS. Thus, Wisley Garden stands out as the correct answer.